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Title:
INTERFERENCE MEASUREMENT AMONG MULTIPLE TRANSMISSION POINTS
Document Type and Number:
WIPO Patent Application WO/2013/110220
Kind Code:
A1
Abstract:
An apparatus, method and program storage for transmitting and receiving an interference measurement resource element set, the interference measurement resource element set configured for performing a direct interference measurement and/or indirect interference derivation measurement, wherein the interference measurement resource element set comprises at least one non-zero power resource element and at least one zero power resource element.

Inventors:
ZHU JIANCHI (CN)
ZHANG ZHI (CN)
Application Number:
PCT/CN2012/070744
Publication Date:
August 01, 2013
Filing Date:
January 29, 2012
Export Citation:
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Assignee:
NOKIA CORP (FI)
ZHU JIANCHI (CN)
ZHANG ZHI (CN)
International Classes:
H04B15/00; H04W24/10
Domestic Patent References:
WO2011105726A22011-09-01
WO2009113951A12009-09-17
Foreign References:
CN102149124A2011-08-10
US20100197330A12010-08-05
CN102300244A2011-12-28
Attorney, Agent or Firm:
KING & WOOD MALLESONS (East Tower World Financial Centre,No. 1 Dongsanhuan Zhonglu, Chaoyang District, Beijing 0, CN)
Download PDF:
Claims:
WHAT IS CLAIMED IS:

1. A method, comprising:

receiving an interference measurement resource element set;

performing an interference measurement on the received resource element set; wherein the interference measurement resource element set comprises at least one non-zero power resource element and/or at least one zero power resource element.

2. The method according to claim 1, wherein the interference measurement resource element set is received via common radio resource control signalling or dedicated radio resource control signalling.

3. The method according to claim 1, wherein a sub set of the interference measurement resource element set is received.

4. The method according to claim 3, wherein the interference measurement resource element set is configured to specific user equipment.

5. The method according to claim 1, wherein the interference measurement resource element set is included in a channel state information resource signal resource element.

6. The method according to claim 5, wherein the interference measurement resource element set include instructions to mute at least one set of resource elements and set those muted resource elements as interference measurement regions.

7. The method according to claim 5, wherein the interference measurement resource element set include instructions to set at least one set of non-muted resource elements as interference measurement regions.

8. A method, comprising: performing an interference measurement based upon an interference measurement resource element set which is predefined and commonly known by both a communication network and one or more user equipment,

wherein the interference measurement resource element set comprises at least one non-zero power resource element and/or at least one zero power resource element.

9. The method according to claim 8, where the interference measurement resource element set is received via common radio resource control signalling or dedicated radio resource control signalling.

10. The method according to claim 8, where a sub set of the interference measurement resource element set is received.

11. The method according to claim 8, wherein the interference measurement resource element set is configured to specific user equipment.

12. The method according to claim 8, wherein the interference measurement resource element set is included in physical downlink shared channel resource element.

13. The method according to claim 8, wherein the interference measurement resource element set include instructions to mute at least one set of resource elements and set those muted resource elements as interference measurement regions.

14. The method according to claim 8, wherein the interference measurement resource element set include instructions to set at least one set of non-muted resource elements as interference measurement regions.

15. A method, comprising:

transmitting an interference measurement resource element set, said interference measurement resource element set configured for performing an interference measurement, wherein the interference measurement resource element set comprises at least one non-zero power resource element and/or at least one zero power resource element.

16. The method according to claim 15, where the interference measurement resource element set is transmitted via common radio resource control signalling or dedicated radio resource control signalling.

17. The method according to claim 15, where a sub set of the interference measurement resource element set is transmitted.

18. The method according to claim 15, wherein the interference measurement resource element set is configured to specific user equipment.

19. The method according to claim 15, wherein the interference measurement resource element set is included in a physical downlink shared channel resource element.

20. The method according to claim 15, wherein the interference measurement resource element set include instructions to mute at least one set of resource elements and set those muted resource elements as interference measurement regions.

21. The method according to claim 15, wherein the interference measurement resource element set include instructions to set at least one set of non-muted resource elements as interference measurement regions.

22. An apparatus, comprising:

at least one processor; and

at least one memory storing a computer program;

in which the at least one memory with the computer program is configured with the at least one processor to cause the apparatus to at least:

receive an interference measurement resource element set;

performing an interference measurement on the received resource element set, wherein the interference measurement resource element set comprises at least one non-zero power resource element and/or at least one zero power resource element.

23. The apparatus according to claim 22, where the apparatus is further configured to receive the interference measurement resource element set via common radio resource control signalling or dedicated radio resource control signalling.

24. The apparatus according to claim 22, where a sub set of the interference measurement resource element set is received.

25. The apparatus according to claim 22, wherein the interference measurement resource element set is configured to specific user equipment.

26. The apparatus according to claim 22, wherein the interference measurement resource element set is included in a channel state information resource signal resource element.

27. The apparatus according to claim 22, wherein the interference measurement resource element set include instructions to mute at least one set of resource elements and set those muted resource elements as interference measurement regions.

28. The apparatus according to claim 22, wherein the interference measurement resource element set include instructions to set at least one set of non-muted resource elements as interference measurement regions.

29. An apparatus, comprising:

at least one processor; and

at least one memory storing a computer program;

in which the at least one memory with the computer program is configured with the at least one processor to cause the apparatus to at least:

perform an interference measurement based upon an interference measurement resource element set which is predefined and commonly known by both a communication network and one or more user equipment,

wherein the interference measurement resource element set comprises at least one non-zero power resource element and/or at least one zero power resource element,

30. The apparatus according to claim 29, wherein the interference measurement resource element set is configured to specific user equipment.

31. The apparatus according to claim 29, wherein the interference measurement resource element set is included in physical downlink shared channel resource element.

32. The apparatus according to claim 29, wherein the interference measurement resource element set include instructions to mute at least one set of resource elements and set those muted resource elements as interference measurement regions.

33. The apparatus according to claim 29, wherein the interference measurement resource element set include instructions to set at least one set of non-muted resource elements as interference measurement regions.

34. An apparatus, comprising:

at least one processor; and

at least one memory storing a computer program;

in which the at least one memory with the computer program is configured with the at least one processor to cause the apparatus to at least:

transmit an interference measurement resource element set, said interference measurement resource element set configured for performing an interference measurement,

wherein the interference measurement resource element set comprises at least one non-zero power resource element and/or zero power resource element.

35. The apparatus according to claim 34, where the apparatus is further configured to transmit the interference measurement resource element set via common radio resource control signalling or dedicated radio resource control signalling.

36. The apparatus according to claim 34, where a sub set of the interference measurement resource element set is transmitted.

37. The apparatus according to claim 34, wherein the interference measurement resource element set is configured to specific user equipment.

38. The apparatus according to claim 34, wherein the interference measurement resource element set is included in a physical downlink shared channel resource element.

39. The apparatus according to claim 34, wherein the interference measurement resource element set include instructions to mute at least one set of resource elements and set those muted resource elements as interference measurement regions.

40. The apparatus according to claim 34, wherein the interference measurement resource element set include instructions to set at least one set of non-muted resource elements as interference measurement regions.

41. An apparatus, comprising:

means for receiving an interference measurement resource element set; and means for performing an interference measurement on the received resource element set;

wherein the interference measurement resource element set comprises at least one non-zero power resource element and/or at least one zero power resource element.

42. An apparatus, comprising:

means for performing an interference measurement based upon an interference measurement resource element set which is predefined and commonly known by both a communication network and one or more user equipment,

wherein the interference measurement resource element set comprises at least one non-zero power resource element and/or at least one zero power resource element.

43. An apparatus, comprising:

means for transmitting an interference measurement resource element set, said interference measurement resource element set configured for performing an interference measurement,

wherein the interference measurement resource element set comprises at least one non-zero power resource element and/or at least one zero power resource element.

44. A program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine for performing operations, said operations comprising:

receiving an interference measurement resource element set;

performing an interference measurement on the received resource element set, wherein the interference measurement resource element set comprises at least one non-zero power resource element and/or at least one zero power resource element.

45. A program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine for performing operations, said operations comprising:

performing an interference measurement based upon an interference measurement resource element set which is predefined and commonly known by both a communication network and one or more user equipment,

wherein the interference measurement resource element set comprises at least one non-zero power resource element and/or at least one zero power resource element.

46. A program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine for performing operations, said operations comprising: transmitting an interference measurement resource element set, said interference measurement resource element set configured for performing an interference measurement,

wherein the interference measurement resource element set comprises at least one non-zero power resource element and/or at least one zero power resource element.

Description:
INTERFERENCE MEASUREMENT AMONG

MULTIPLE TRANSMISSION POINTS

TECHNICAL FIELD:

The exemplary and non-limiting embodiments of this invention relate generally to wireless communication systems, methods, devices and computer programs and, more specifically, relate to providing interference measurements across multiple downlink (DL) transmission points in diverse coordinated multi-point (CoMP) transmission schemes.

BACKGROUND:

This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived, implemented or described. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.

The following abbreviations that may be found in the specification and/or the drawing figures are defined as follows:

CA Carrier Aggregation

CB Coordinated Beam Forming

CC Component Carriers

CoMP Coordinated Multi-Point

CQI Channel Quality Indicator

CRS Common Reference Signals

CS Coordinated Scheduling

CSI Channel State Information

CSI RE Channel State Information Reference Symbols DL Downlink

DPB Dynamic Point Blanking

DPS Dynamic Point Selection

ICI Inter-Cell Interference

IM Interference Measurement

JP Joint Processing

JT Joint Transmission

PDSCH Physical Downlink Shared Channel

PMI Precoding Matrix Indicator

RE Resource Element

RRC Radio Resource control

RRH Remote Radio Head

RS Reference Signal

TP Transmission Point

Coordinated multi-point (CoMP) transmission is considered for Long Term Evolution Advanced (LTE-A) as a key technique to reach the requirement of IMT- Advanced. In particular, CoMP promises to achieve this by increasing collaboration between different transmission/reception points (e.g., base stations, repeaters, or hotspots, etc.) in both downlink (DL) transmissions and uplink (UL) receptions from and to user equipment (UE) simultaneously and on the same frequency resources. By coordinating and combining signals from multiple antennas, CoMP promises to make it possible for (but has not yet allowed) mobile users to enjoy consistent performance and quality when they access and share videos, photos and other high-bandwidth services whether they are close to the center of an LTE-A cell or at its outer edges.

In DL and UL CoMP, the transmissions and reception from or to multiple cells are coordinated in so-called CoMP clusters such as to mitigate inter-cell interference among the cells at the UE. The CoMP cluster can vary in size from a two or more transmission point (TP) cluster with one TP designated as a serving cell and the remaining TPs designated as coordinating cells. To support CoMP cluster operations knowledge of channel state information (CSI) feedback from the UE to the eNBs is required to support operations. The CSI feedback could take the form of, for example, a precoding matrix indication (PMI), or other form of CSI that allows weighting and evolved Node B base station (eNB) antennas in order to mitigate interference in the spatial domain. Also, a backhaul infrastructure is required to communicate data and control information received by each coordinated cell to the serving cell.

For accurate channel quality indicator (CQI) reporting and link adaptation, the UE must estimate both channel and inference correctly. However, conventional interference measurement among UE cannot distinguish different sources of interference. Even with the same transmission scheme, the interference measurement (IM) set and transmission set of each UE may be different depending upon the location, channel state of the UE.

FIG. 1 demonstrates three different DL transmission edge scenarios in a three transmission point CoMP cluster. In particular, FIG. 1 illustrates a first scenario where a UE is closely located to a single transmission point, UEs located at the boundary of two transmission points, and a UE located at the boundary of three transmission points. As shown in FIG.l, UE 1 is located closely to DL transmission point (TP) 1 and receives interference from TP 2 and TP 3. UE 2 and UE 4 are located at the boundary of two transmission points. For example, UE 2 is located at the boundary of TP 1 and TP 2 coverage area with TP 3 regarded as an interference source. Similarly, UE 4 is located at the boundary of TP l 's coverage area and TP 3's coverage area with TP 2 regarded as an interference point. Finally, UE 3 is located at the boundary of TPl 's , TP 2's, and TP 3's coverage area with no transmission points regarded as an inference source. Instead, interference comes from outside the three transmission points.

SUMMARY: The below summary section is intended to be merely exemplary and non-limiting.

The foregoing and other problems are overcome, and other advantages are realized, by the use of the exemplary embodiments of this invention. In one exemplary embodiment of the invention there is provided a method which includes method steps for receiving an interference measurement resource element set. Upon receiving the interference measurement resource element set, the method further includes the step of performing a direct interference measurement and/or indirect interference derivation measurement. The interference measurement resource element set includes non-zero power resource elements and/or zero power resource elements.

In another exemplary embodiment of the invention there is provided a method which includes method steps for performing an interference measurement based upon a interference measurement resource element set which is predefined and commonly known by both a communication network and one or more user equipment, wherein the interference measurement resource element set comprises non-zero power resource elements and/or zero power resource elements.

In another exemplary embodiment of the invention there is provided a method which includes method steps for transmitting an interference measurement resource element set. The interference measurement resource element set includes non-zero power resource elements and/or zero power resource elements.

In yet another exemplary embodiment of the invention, an apparatus is disclosed which is configured to receive an interference measurement resource element set. Upon receiving the interference measurement resource element set the apparatus performs a direct interference measurement and/or indirect interference derivation measurement. The interference measurement resource element set includes non-zero power resource elements and/or zero power resource elements.

In another exemplary embodiment of the invention there is provided an apparatus which is configured to perform an interference measurement based upon a interference measurement resource element set which is predefined and commonly known by both a communication network and one or more user equipment, wherein the interference measurement resource element set comprises non-zero power resource elements and/or zero power resource elements.

In another exemplary embodiment of the invention, an apparatus is disclosed which is configured to transmit an interference measurement resource element set. The interference measurement resource element set includes non-zero power resource elements and/or zero power resource elements.

In yet another exemplary embodiment of the invention there is provided a non-transitory computer readable medium storing a program of machine-readable instructions executable by a digital processing apparatus of a computer system to perform operations for controlling computer system actions. The operations comprising operation which receives an interference measurement resource element set. Upon receiving said interference measurement resource element set a direct interference measurement and/or indirect interference derivation measurements are preformed. The interference measurement resource element set includes non-zero power resource elements and zero power resource elements.

In another exemplary embodiment of the invention there is provided a non-transitory computer readable medium storing a program of machine-readable instructions executable by a digital processing apparatus of a computer system to perform operations for controlling computer system actions. The operations comprising operations which perform interference measurements based upon an interference measurement resource element set which is predefined and commonly known by both a communication network and one or more user equipment, wherein the interference measurement resource element set comprises non-zero power resource elements and/or zero power resource elements.

In another exemplary embodiment of the invention there is provided a non-transitory computer readable medium storing a program of machine-readable instructions executable by a digital processing apparatus of a computer system to perform operations for controlling computer system actions. The operations comprising operation which transmits an interference measurement resource element set. The interference measurement resource element set comprises non-zero power resource elements and/or zero power resource elements.

BRIEF DESCRIPTION OF THE DRAWINGS

The following discussion of the exemplary embodiments of this invention is made more evident in the following Detailed Description, when read in conjunction with the attached Drawing Figures, wherein:

Figure 1 depicts three different DL transmission edge scenarios in a three transmission point CoMP cluster;

Figure 2 is a logical diagram illustrating a method or computer program, operational for interference measurement across multiple downlink (DL) transmission points in diverse coordinated multi-point (CoMP) transmission schemes in accordance with exemplary embodiment of the invention;

Figure 3 is an illustration of IM RE set employing CSI RS REs in accordance with exemplary embodiments of the invention;

Figure 4 is an illustration of IM RE set employing a sub set of CSI RS REs in accordance with exemplary embodiments of the invention;

Figure 5(a) is, an illustration of IM RE set employing PDSCH REs which is known to a plurality of UEs in accordance with exemplary embodiments of the invention;

Figure 5(b) is, an illustration of IM RE set employing a sub set of PDSCH REs which is known to a plurality of UEs in accordance with exemplary embodiments of the invention;

Figure 6 is an illustration of an IM RE set employing either CSI RE or PDSCH RE in accordance with exemplary embodiments of the invention; and Figure 7 is a simplified block diagram of various electronic devices and apparatuses that are suitable for use in practicing the exemplary embodiments of this invention.

DETAILED DESCRIPTION:

The exemplary embodiments of this invention provide apparatuses, methods, and computer program(s) that allow for interference measurement across multiple downlink (DL) transmission points in diverse coordinated multi-point (CoMP) transmission schemes.

There are several different transmission schemes available for DL CoMP techniques which are deployed to provide adequate coverage in difference edge scenarios as shown in FIG. 1. They include coordinated scheduling beamforming (CS/CB) and joint processing (JP), corresponding to single point and multiple points coordinated transmission, respectively. In CS/CB, single point transmissions are coordinated via scheduling decisions and transmitted by beam selection among multiple cells which reduces the inter-cell interference. On the other hand, JP techniques include joint transmission (JT) , where data is shared among multiple points to one or multiple user equipments (UEs) simultaneously so as to achieve the performance gain by signal combining and interference nulling from multiple points. Also, JP techniques include Dynamic Point Selection (DPS), where a UE can receive data from a single transmission point at every subframe. This transmission point can change dynamically within the CoMP set.

Four deployment scenarios for 3GPP Rel-11 CoMP were agreed to at the Dublin RAN# 63 meeting which took place between January 17 - 21 , 2011. Those four deployment scenarios are as follows:

Scenario 1 : Homogeneous network with intra-site CoMP;

Scenario 2: Homogeneous network with high Tx power remote radio heads (RRHs); Scenario 3: Heterogeneous network with low power RRHs within the macrocell coverage where the transmission/reception points created by the RRHs have different cell IDs (i.e. pico cells); and

Scenario 4: Network with low power RRHs within the macrocell coverage where the transmission/reception points created by the RRHs have the same cell IDs as the macro cell (i.e. in a distributed antenna system (DAS)).

Currently ongoing in Release 1 1 are studies to address several scenarios and schemes for which common reference signals (CRS) -based interference estimation might not be suitable, for example, in a deployment scheme with geographically distributed antennas with a shared cell ID. In such a scenario, the CRS would be transmitted in a single frequency network (SFN) manner from all points corresponding to the same cell ID. As such, if the actual PDSCH transmissions are originating only from a subset of points, the interference estimated from CRS would clearly not match with the interference seen during the PDSCH data transmissions. As a result the reported CQI would be mismatched.

An example of a scenario where CRS might not be suitable is where CoMP requires that the UE estimate/report CQI based on a hypothesis about CoMP transmission instead of (or in addition to) single-cell/point transmission. In this scenerio, the UE should be able to estimate interference underlying the CoMP transmission. However, CRS are not suitable for this purpose especially if colliding CRS are configured for example to avoid the overhead problems related to CRS frequency shifts with joint processing CoMP schemes.

Another issue which complicates interference measurement is the increased usage of Multicast/Broadcast over a Single Frequency Network (MBSFN) subframes. In MBSNF the UE has fewer opportunities to perform interference measurements on CRS. From this perspective it would be beneficial to have some support of interference measurements that is applicable also in MBSFN subframes.

Recently, carrier aggregation with extension carrier has been suggested which has the possibility to reduce CRS density or eliminate CRS. Non-backward-compatible carrier without CRS would be introduced in Release 12 or beyond. Such new scenarios could also imply a need for further support of UE interference measurements for CSI reporting.

As described below exemplary embodiments of the present invention provide for interference measurement across multiple downlink (DL) transmission points in diverse coordinated multi-point (CoMP) transmission schemes. In other words, the various embodiments provide a dynamic configuration solution for different CoMP schemes where different types of interference are seen by a CoMP UE.

For example, in joint transmission (JT) the PDSCH experiences interference from all the points/cells outside of the joint transmission set. The transmission set in the actual joint transmission may or may not be known to the UE, which may lead to mismatch between the transmission set assumed by the UE in the CQI report and the actual transmission set in the scheduled joint transmission. A more accurate assumption on interference points is achieved if the transmission set is semi-statically configured.

In Dynamic Point Selection (DPS), the desired part of the signal is related to the dynamically selected transmission point, while signals from all other points/cells will be interference. Considering CQI measurements for each point in the CoMP measurement set, channel and interference needs to be measured correspondingly based on the assumption of the transmission point selection.

For CS/CB, the point/cell that transmits the PDSCH is static, which results in that all signals not originating from that point/cell are considered as interference. In the case of CS/CB, the spatial characteristics of the precoder from each interference point is considered.

Table 1 describes the interference assumptions for each of the above described CoMP schemes. Table 1 : Interference assumption for each CoMP scheme

Referring now to FIG. 2, a method or computer program, operational to perform interference measurement across multiple downlink (DL) transmission points in diverse coordinated multi-point (CoMP) transmission schemes, is shown in accordance with exemplary embodiment of the invention. In FIG. 2, a down link transmission point (DL TP) transmits a signal to user equipment (UE) with the signal including an interference measurement resource element (IM-RE) set 210. In one exemplary embodiment, a TP signals a UE with the IM-RE set. In an alternative embodiment the IM-RE set is predefined and commonly known by the UE and TP. Some non-limiting examples of a TP are a base station such as an enhanced eNode base station (eNB), a repeater such as a remote radio head (RRH), an access point (AP) or hotspot. The TP can transmit the IM-RE set via common radio resource control (RRC) signalling or dedicated RRC signalling. An alternative embodiment can provide that the DL TP transmits a subset of the IM-RE. In this alternative embodiment where a sub set is transmitted by the DL TP, the REs can be configured to be UE specific.

Another optional embodiment can provide that the method and computer program operate such that the DL TP transmits a CQI definition or an interference hypothesis. As shown in FIG, 2, this transmission can occur after the step of transmitting the IM-RE set or sub set (or prior to that step). The CQI definition can be set at a default value. In this alternative embodiment, an eNB can notify UE which kind of CQI definition or interference hypothesis should be reported. Hence, the UE perform interference measurement according to the signalled CQI definition or interference hypothesis.

Various embodiments described below are described for configuring the IM-RE set or subset in the CoMP cluster to include channel state information resource signal resource element (CSI RS RE) or included (within the control information) in the physical downlink shared channel (PDSCH) RE.

The methods and computer programs suitable for carrying out exemplary embodiments of the invention employ zero-power and non-zero -power techniques for specifying resource elements (REs) for interference measurement (IM), In a zero-power CSI RS based interference measurement, the DL TP serving cell along with the DL TP coordinating cells "mute" a set of resource elements (REs) and set those REs as an interference measurement region. In other words, the eNB does not transmit anything on the muted resource element (RE) as such transmission power on this RE is zero. Alternatively, in a non-zero-power RE method, the DL TP serving cell along with the DL TP coordinating cells set those non-muted REs as an interference measurement region. Hence, in non-zero -power, the eNB can transmit something on this RE (i.e. PDSCH, CSI-RS, etc.).

Based on the configured REs for IM, the UE can obtain the expected IM 220 by direct measurement 222 on the IM REs or by indirect interference derivation measurement 224 from a combination of measurements on the multiple IM REs. Alternatively, the UE can obtain an interference measurement from a combined direct measurement and indirect interference derivation measurement 226.

Referring now to FIG. 3, an illustration of an IM RE set employing CSI RS REs 300 in accordance with exemplary embodiments of the invention is provided. In particular, FIG. 3 depicts three DL TPs in a CoMP interference measurement set. In FIG. 3, each TP is configured such that one set of non-zero -power CSI-RS REs (one or multiple REs) and two sets of zero-power CSI-RS REs are indicated. For the same RE, only one TP is configured non-zero-power CSI-RS and the other two TPs are configured zero-power CSI-RS.

In FIG. 3, TP1 is the serving cell for one or more UEs (not shown), through channel estimation and power measurement on RE1 of TP1, the UE can obtain the interference outside of TP1, TP2 and TP3. In one embodiment an interference measurement monitor (IMM) can measure I 0llt . From RE1 perspective, this kind of interference estimate is beneficial for joint transmission (JT) over three TPs, dynamic muting, and coordinated beamforming (CB) over three TPs. Accordingly, the UE employs direct interference measurement 222 as shown in FIG. 2.

Through power measurement on RE2 of TP1, UE1 can obtain the interference from TP 2 as well as I out , (i.e. I out + I 2 ). From RE2 perspective, this kind of interference estimate is beneficial for JT over two TPs, TP1 + TP3, dynamic muting, and coordinated beamforming over two TPs, TP1 + TP3. Accordingly, the UE employs direct interference measurement 222 as shown in FIG. 2.

Through power measurement on RE3 of TP1, UE1 can obtain the interference from TP3 as well as I out (i.e. I out + I 3) . From RE3 perspective, this kind of interference estimate is beneficial for JT over two TPs, TP1+TP2, dynamic muting, and coordinated beamforming over three TPs, TP1+TP2. Accordingly, the UE employs direct interference measurement 222 as shown in FIG. 2.

Combining the above three measurement results (RE1, RE2 and RE3), the UE can derive I out + ¾ + I 3 . This kind of interference estimate is beneficial for DPS. Accordingly, the UE employs indirect interference derivation measurement 224 as shown in FIG. 2.

Referring now to FIG. 4, there is an illustration of an IM RE set employing a sub set of CSI RS REs 400 in accordance with exemplary embodiments of the invention. As shown in FIG. 4, an IM RE is CSI-RS RE and three TPs are in the CoMP CSI measurement set. Each TP is configured with two sets of non-zero-power CSI-RS REs (one or multiple REs) and one set of zero-power CSI-RS REs. For the same RE, only one TP is configured zero-power CSI-RS and the other two TPs are configured non-zero -power CSI-RS. In FIG. 4, TP1 is the serving cell for UEl (not shown) and TP2 is the serving cell for UE2 (not shown). In this scenario, UEl and UE2 obtain different interference information.

Through channel estimation and power measurement of REl of TP1, UEl can obtain interference I ou t+l3 - This kind of interference estimate is beneficial for JT over two TPs, TP1 + TP2, DPB, and coordinated beamforming over two TPs, TP1 + TP2. Accordingly, the UE employs direct interference measurement 224 as shown in FIG. 2.

Through channel estimation and power measurement of RE2 of TP1, UEl can obtain interference I out +l2- This kind of interference estimate is beneficial for JT over two TPs, TP1 + TP3, DPB, and coordinated beamforming over two TPs, TP1 + TP3. Accordingly, the UE employs direct interference measurement 224 as shown in FIG. 2.

Through power measurement of RE3 of TP1, UEl can obtain interference I out + ¾+ I 3 . This kind of interference estimate is beneficial for DPS. Accordingly, the UE employs direct interference measurement 224 as shown in FIG. 2.

I out can be derived based on the above three measurement results. This kind of interference estimate is beneficial for JT or CB. Accordingly, the UE employs indirect interference derivation measurement 224 as shown in FIG. 2.

The UE can also be configured to see a subset of the IM-RE-Set. For example, UEl can be configured to see subset 2 (410a) and UE2 can be configured to see subset 1 (420). This is useful when the coordination area, (i.e. transmission points in the edges of the cells) are different for each UE.

Referring now to FIG. 5(a) and (b), an illustration of IM RE set employing PDSCH 500A/500B which is known to a plurality of UEs in accordance with exemplary embodiments of the invention. In this embodiment, if IM RE is PDSCH RE, then the information provided in the form of non-zero-power PDSCH RE is pre-defined and known to the UE. In other words the step of transmitting a IM RE set 210 from a DL TP as shown in FIG. 2 does not occur. However, as shown in FIG. 5(a) the serving cell (TP1) for one or more UEs (not shown), allows a UE to obtain the interference outside of TP1, TP2 and TP3. This is accomplished through channel estimation and power measurement on RE1 of TP1 as described above with reference to FIG. 3. The only difference is PDSCH REs are utilized instead of CSI REs (and the TP does not transmit the IM set). Also, FIG. 5(b) demonstrates a similar embodiment as that shown in FIG. 4 with the exception of replacing PDSCH REs with CSI REs.

Referring now to FIG. 6, an illustration of an IM RE set employing either CSI RE or PDSCH RE 600 is shown in accordance with exemplary embodiments of the invention. In FIG. 6, zero-power REs for all TPs can be included. In this embodiment, I out can be obtained through direct measurement on RE4. However, this creates more overhead that the other non-limiting examples of the invention.

Reference is now made to FIG. 7 for illustrating a simplified block diagram of various electronic devices and apparatuses 700 that are suitable for use in practicing the exemplary embodiments of this invention. In FIG. 7, a first access node 760N is adapted for communication over a wireless link A with a mobile apparatus, such as a mobile terminal or UE 750n. The first access node 760N may be a macro eNodeB, a femto eNodeB, or other type of base station (BS) or access point (AP).

For completeness, the UE 750N includes processing means such as at least one data processor (DP) 750A, a storing means such as at least one computer-readable memory (MEM) 750B storing at least one computer program (PROG) 750C, and also a communicating means such as a transmitter TX 750D and a receiver RX 750E for bidirectional wireless communications with the first access node 750 via one or more antennas 750F. UE 750 includes at least one of the PROGs 750C to allow the UE to employ a direct interference measurement and indirect interference derivation measurement. Power measurements can be measured at I ou t, Ii, h, and in the interference measurement monitor (IMM) 752A within UE 750N in accordance with the above described methods and computer programs. Implementation may at least be in part by executable computer software, or by hardware, or by a combination of software and hardware (and firmware).

The first access node 760N similarly includes processing means such as at least one data processor (DP) 760A, storing means such as at least one computer-readable memory (MEM) 760B storing at least one computer program (PROG) 760C, and communicating means such as a transmitter TX 760D and a receiver RX 760E for bidirectional wireless communications with the UE 760 via one or more antennas 760F. First access node 760 also includes at least one of the PROGs 760C to allow it to transmit an interference measurement set via CSI RS RE 764P or PDSCH RE 762P.

Also as shown in FIG. 7 a data and/or control path SI couples the first access node 760N with a MME/S-GW 780.

MME/S-GW 780 includes processing means such as at least one data processor (DP) 780A, a storing means, such as at least one computer-readable memory (MEM) 780B storing at least one computer program (PROG) 780C, and a communicating means, such as a modem 780H for bidirectional communication with the first access node 760N via the link SI . While not particularly illustrated for the UE 75 ON or first access node 760N, those devices are also assumed to include as part of their wireless communicating means a modem which may be inbuilt on a radiofrequency RF front end chip within those devices 760F, 750F, 780H and which chip also carries the TX 760D/50D and the RX 760E/750E. The MME/S-GW 780 also has stored in its local memory at 780B the database which it constructs and maintains as detailed above and listing the CoMP transmission schemes available among a CoMP cluster as well as designation of a serving cell and coordination cell in the cluster.

At least one of the PROGs 760C in the eNB 760N is assumed to include program instructions that, when executed by the associated DP 760 A, enable the device to operate in accordance with the exemplary embodiments of this invention, as detailed above. In particular, to allow the eNB 760N to operate in conjunction with UE 750N determine the listing of CoMP transmission schemes available among the CoMP cluster as well as designation of a serving cell and coordination cell in the cluster.

In these regards, the exemplary embodiments of this invention may be implemented at least in part by computer software stored on the MEM 760B, which is executable by the DP 760A of the eNB 760N or by hardware, or by a combination of tangibly stored software and hardware (and tangibly stored firmware). Electronic devices implementing these aspects of the invention need not be the entire devices as depicted at FIG. 7, but exemplary embodiments may be implemented by one or more components of same such as the above described tangibly stored software, hardware, firmware and DP, or a system on a chip SOC or an application specific integrated circuit ASIC. The above described methods and computer programs can run on any external device that can communicate with the eNB such non-limiting examples are a user equipment such as a cellular phone, smart phone, tablet or personal computer.

Various embodiments of the computer readable MEMs 760B, 750B, 780B include any data storage technology type which is suitable to the local technical environment, including, but not limited to, semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, removable memory, disc memory, flash memory, DRAM, SRAM, EEPROM and the like. Various embodiments of the DPs 780A, 780A and 780A include, but are not limited to, general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and multi-core processors.

Further, some of the various features of the above non-limiting embodiments may be used to advantage without the corresponding use of other described features. The foregoing description should therefore be considered as merely illustrative of the principles, teachings and exemplary embodiments of this invention, and not in limitation thereof.

Various modifications and adaptations to the foregoing exemplary embodiments of this invention may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings. However, any and all modifications will still fall within the scope of the non-limiting and exemplary embodiments of this invention.

For example, while the exemplary embodiments have been described above in the context of the UTRAN LTE-A system, it should be appreciated that the exemplary embodiments of this invention are not limited for use with only this one particular type of wireless communication system, and that they may be used to advantage in other wireless communication systems, as well as in systems using different combination of technologies (e.g., other than or in addition to LTE cellular, LTE-A cellular, GNSS, Bluetooth and WiFi, which are discussed merely as examples and not in a limiting sense).

It should be noted that the terms "connected," "coupled," or any variant thereof, mean any connection or coupling, either direct or indirect, between two or more elements, and may encompass the presence of one or more intermediate elements between two elements that are "connected" or "coupled" together. The coupling or connection between the elements can be physical, logical, or a combination thereof. As employed herein two elements may be considered to be "connected" or "coupled" together by the use of one or more wires, cables and/or printed electrical connections, as well as by the use of electromagnetic energy, such as electromagnetic energy having wavelengths in the radio frequency region, the microwave region and the optical (both visible and invisible) region, as several non-limiting and non-exhaustive examples.

Further, the various names used for the described parameters, modes of operation, subframes, reports and the like (e.g., CQI report, CSI report, CSI RS, etc.) are not intended to be limiting in any respect, as these parameters, modes of operation, subframes, reports and the like may be identified by any suitable names. Further, any names assigned to various channels (e.g., PDCCH, etc.) are not intended to be limiting in any respect, as these channels may be identified by any suitable names.

Furthermore, some of the features of the various non-limiting and exemplary embodiments of this invention may be used to advantage without the corresponding use of other features. As such, the foregoing description should be considered as merely illustrative of the principles, teachings and exemplary embodiments of this invention, and not in limitation thereof.